Real-Time check all transactions to an Ethereum address using Web3.js

This tutorial will teach you the basics of web3.js, the JavaScript API for interacting with the Ethereum network. We’ll be building 2 scripts that will both accomplish the same thing: monitor transactions to a given Ethereum address. The first script is very slow and network and resource intensive, while the second is more elegant and less heavy on the network and system.

Timestamps:
00:00 - Introduction to web3.js
2:00 - Explanation and coding of method 1
13:21 - Explanation and coding of method 2
23:29 - Testing both scripts

Links:
Version 1 code
https://gist.github.com/jonasbostoen/e5de8af0e4436843a4ef59c4e9830b49 
Version 2 code
https://gist.github.com/jonasbostoen/723a41383fd901a3dec6030d2c6a929f 
Web3.js API Documentation
https://web3js.readthedocs.io/en/v1.2.1/ 

via Polycode

#ethereum #blockchain #node #javascript #web3

Intro to Web3.js · Ethereum Blockchain Developer Crash Course

Today I’m going to you how to get started using the Web3.js  library, the main JavaScript library for interacting with The Ethereum Blockchain. I’ll show you what Web3.js is, how to use it to talk to the Ethereum blockchain in this 8-part tutorial series.

• What is Web3.js?
• Read Data from Smart Contracts with Web3.js

• Inside Ethereum Transactions

• Deploying Smart Contracts with Web3.js

• Calling Smart Contract Functions with Web3.js

• Smart Contract Events with Web3.js

• Inspecting Blocks with Web3.js

• Web3.js Utilities

#web3 #ethereum #blockchain #javascript

Building A Blockchain App with Ethereum, Web3.js & Solidity Smart Contracts

I’m going to show you how to create your first blockchain application with Ethereum, Web3.js, and Solidity smart contracts. You don’t have to know anything about blockchain to follow along. I’ll teach you from scratch. Use this step-by-step guide with code examples and written instructions to start your blockchain developer journey today!

I’ll take you over the shoulder to build a full blockchain application in the 3-hour video above. You can also follow along with the step-by-step instructions in this guide.

Table of Contents

• Introduction
  • What Are We Going To Build?
  • What Is A Blockchain?
  • What Is A Smart Contract?
  • How Does A Blockchain App Work?
• Tutorial Steps
  • Installing Dependencies
  • Part 1: Project Setup
  • Part 2: Sell Products
  • Part 3: Buy Products
  • Part 4: Marketplace Website Setup (Front End)
  • Part 5: Sell Products (Front End)
  • Part 6: Buy Products (Front End)
  • Part 7: Deploy Project

#blockchain #ethereum #web3 #solidity

What is Web3? The Decentralized Internet of the Future Explained

Learn the differences between Web2 and Web3, and why many developers and companies are shifting their approach in building apps.

If you’re reading this, you are already participating in the modern web (Web 2.0). The web we experience today is much different than what it was just 10 years ago (Web 1.0). And with Web3, it’s getting ready to change again.

In this article, I will lay out how the web has evolved, where’s it going next, and why this matters.

If history has taught us anything, these changes will matter a lot. Think about how the internet affects your life on a daily basis. Consider how society has changed as a result of the internet. Social media platforms. Mobile apps. And now the internet is going through another paradigm shift as we speak.

#web-development #web3 #developer

How to Break into Ethereum, Crypto, and Web3 as a Developer

Lately, I’ve been talking about my move into the Web3, Ethereum, and crypto space since making the switch from a traditional web, mobile, and cloud background.

Since making that move, a shocking number of people have reached out to me who are also thinking about doing the same.

It’s really great to see so many other people interested in these fields. And if I’m being honest – it feels validating to know that so many others are also on the fence and are so deeply interested in the space as well.

As for me, I was nervous about making the career switch. Moving into a completely new area of specialization, with a technology I was still getting ramped up on, and a community I was not yet involved with, was a big leap. Especially compared to a very comfortable role with a FAANG company that paid really well (and a team that I really loved).

After over a month, I have zero regrets with the change. I’m also the happiest I’ve been in a long time, and am excited and energized about the things I have the opportunity to work on everyday.

I decided to write this post to give a blueprint for anyone looking to get into blockchain, crypto, Ethereum, and Web3 from a traditional development background. I can point people to this blog post the next time I get asked how to get into the space.

I’ll break this article up into a few main parts:

1. Technologies and resources to learn
2. Tradeoffs and considerations
3. People to follow
4. Companies hiring and doing interesting stuff
5. General tips and landing a job

Let’s dive in.

#crypto #web3 #developer #ethereum #blockchain

Intro to Web3.py · Ethereum For Python Developers

Today I’m going to you how to get started using the Web3.py  library. If you’re a Python developer, Web3.py is your go-to library for interacting with The Ethereum Blockchain. Today I’ll show you step-by-step how to use Web3.py is to talk to the Ethereum blockchain in this 6-part tutorial series.

Table of Contents

1. What is Web3.py?
2. Read Data from Smart Contracts with Web3.py

3. Sending Ethereum Transactions

4. Calling Smart Contract Functions with Web3.py

5. Deploying Smart Contracts with Web3.py

6. Inspecting Blocks with Web3.py

#web3 #ethereum #python

A Distributed Serverless Blockchain-Based Cache System

Caching is a crucial feature for web3 applications in the matter of scaling. Nowadays, blockchain-based apps struggle to give their users a web2 UX due to decentralization, like querying all of the distributed ledger data (or large size of it), implement complex logic, computations, etc.

If you are going to build a fully decentralized app, completely on-chain, you need to make a choice between decentralization and user experience. It’s a hard choice! Especially if your Dapp has the “ethics” of being user-owned, like the example that will be discussed shortly.

fact: if your platform takes more than ~13-15 secs to display data on the client-side, it will lose users for better competitors that scale.

Implementation:

In this section, we will take a look over decent.land, which is an Arweave based app.

#cache #web3 #blockchain #serverless

FrontierBlockImport and Moonbeam's Dual Parachain/Standalone Runtime

Moonbeam is much more than just an EVM implementation: it’s a highly specialized Layer 1.5 chain that mirrors Ethereum’s Web3 RPC, accounts, keys, subscriptions, logs, and more. The Moonbeam platform extends the base Ethereum feature set with additional features such as on-chain governance, staking, and cross-chain integrations.

#moonbeam #ethereum #substrate #web3 #blockchain

Making a Node.js App to Interact With a Smart Contract the Git Way

Hey everybody, this is the second post of the series on writing apps the Git way, where you just go take a cup of coffee and browse a Git repo to learn something new!

Be sure to take it step by step, if you’re a new kid on the block.

Today we’re going to write a Node.js app for the purpose to interact with our shiny new first Solidity smart contract deployed on the Ropsten testnet already – which remember, basically outputs the

Hello world!string.

The code is available at programarivm/solidity-interacting-with-nodejs.

Here is the git log for you to get the application up and running.

$ git log --oneline 45e59bd (HEAD -> master) app.js is implemented 80195ad npm install web3 dotenv 97a0d34 .gitignore is added fdd0e78 npm init

#blockchain #solidity #cryptocurrency #ethereum #smart-contracts #git #dapps #web3

What Does Filecoin Seek To Achieve?

Filecoin is a novel distributed network protocol that enables a global, decentralized marketplace for data storage.

The highly-anticipated project is rapidly maturing; with the public launch of the main Filecoin network slated for as early as next month, the project has reached a state where developers can begin seriously evaluating the use of Filecoin in their own technology stacks.

The following discussion is offered as a jumping-off point for those looking to do so.

What Filecoin Offers

Filecoin was conceived as an incentivization layer for the InterPlanetary File System (IPFS), a content-addressable, peer-to-peer storage network protocol (it is important to note that despite this history, Filecoin and IPFS are independent projects with no inherent dependencies on one another).

While IPFS addresses the problem of securely sending and receiving data, Filecoin targets the fundamental need for trustworthy, verifiable storage of data.

Thus, from the beginning, Filecoin has been predicated on the desire to properly align incentivize structures to ensure the preservation of some of humanity’s most important information.

To achieve this goal, the Filecoin protocol conceptualizes a novel, decentralized storage marketplace. Juxtaposed against existing cloud storage solutions, its peer-to-peer network is

1. global and distributed, where traditional cloud service providers are highly centralized, and only available in limited locations that are often distant from consumers;
2. efficient and scalable, operating as a content-delivery network to preserve bandwidth and taking advantage of latent storage resources;
3. censorship-resistant;
4. highly amenable to automation via smart contracts;
5. trustless and open, mitigating attempts at vendor lock-in;
6. provably secure and publicly auditable, using content-addressing and constant verification to ensure data authenticity and integrity.

As a result, the Filecoin protocol is expected to manifest as an extremely reliable, low-cost cloud storage solution, bringing to the table several capabilities that other paid alternatives have never been able to offer. To achieve this, it employs a variety of novel crypto-economic constructions.

#filecoin #cloud-storage #distributed-computing #web3 #cloud

The Evolution of dOrg: The Builder DAO

This is the story of dOrg’s evolution from a few passionate engineers to a heterarchical network of builders developing industry-leading Web3 software.

The year is 2020. DAOs are starting to govern everything, from lending and trading protocols to investment funds, insurance pools and prediction markets. But a much simpler use-case has been quietly gaining traction: a development agency called dOrg.

(Disclaimer: The author is a member of dOrg)

Part 1: Single-Celled Origins

dOrg spawned in late 2018 as a 2-of-3 multisig with the mission of enabling decentralized organizations. After successfully shipping the Colony Task Importer and DAOstack Launcher, the team decided to incorporate in order to take on a higher volume of large-scale Web3 projects. Unfortunately, there was no way to grant smart contracts legal personhood at the time… so they invented one!

With the help of the legal minds behind Vermont’s Blockchain-Based LLC legislation, dOrg became the first legally recognized DAO in the US. How?

Step 1: Deploy a DAOStep 2: Register an LLC that references the DAO as its source of governanceStep 3: Boom! You have a DAO that limits liability and can enter legally binding agreements (or, in reverse, an LLC with fully on-chain ownership interests and governance)

#defi #blockchain #web3 #ethereum #cryptocurrency #dao #decentralization #blockchain-top-story

How to Send Transactions with Web3 and NodeJS - Backend Blockchain Development

REGISTER FOR FREE TRAINING “How to find your first 6-Figures Blockchain Developer Job”: https://eattheblocks.com/bootcamp

Code of this tutorial: https://github.com/jklepatch/eatthebl…

Other Links:

- Github repo: https://github.com/jklepatch/eatthebl…

- Forum: https://forum.eattheblocks.com

- Blog: https://eattheblocks.com

#nodejs #web3 #blockchain

How to send transactions with Web3 and Node.JS?

The web3.js library is a collection of modules which contain specific functionality for the ethereum ecosystem.

• The web3-eth is for the ethereum blockchain and smart contracts
• The web3-shh is for the whisper protocol to communicate p2p and broadcast
• The web3-bzz is for the swarm protocol, the decentralized file storage
• The web3-utils contains useful helper functions for Dapp developers.

Adding web3.js

First you need to get web3.js into your project. This can be done using the following methods:

• npm: npm install web3
• meteor: meteor add ethereum:web3
• pure js: link the dist/web3.min.js

After that you need to create a web3 instance and set a provider.
Ethereum supported Browsers like Mist or MetaMask will have a ethereumProvider or web3.currentProvider available. For web3.js, check Web3.givenProvider.
If this property is null you should connect to a remote/local node.

… code-block:: javascript

// in node.js use: var Web3 = require('web3');

var web3 = new Web3(Web3.givenProvider || "ws://localhost:8546");

That’s it! now you can use the web3 object.

const Web3 = require('web3');
const Provider = require('@truffle/hdwallet-provider');
const MyContract = require('./build/contracts/MyContract.json');
const address = '';
const privateKey = '';
const infuraUrl = ''; 

//Hard way (web3#signTransaction() + web3#sendSignedTransaction())
const init1 = async () => {
  const web3 = new Web3(infuraUrl);
  const networkId = await web3.eth.net.getId();
  const myContract = new web3.eth.Contract(
    MyContract.abi,
    MyContract.networks[networkId].address
  );

  const tx = myContract.methods.setData(1);
  const gas = await tx.estimateGas({from: address});
  const gasPrice = await web3.eth.getGasPrice();
  const data = tx.encodeABI();
  const nonce = await web3.eth.getTransactionCount(address);

  const signedTx = await web3.eth.accounts.signTransaction(
    {
      to: myContract.options.address, 
      data,
      gas,
      gasPrice,
      nonce, 
      chainId: networkId
    },
    privateKey
  );
  console.log(`Old data value: ${await myContract.methods.data().call()}`);
  const receipt = await web3.eth.sendSignedTransaction(signedTx.rawTransaction);
  console.log(`Transaction hash: ${receipt.transactionHash}`);
  console.log(`New data value: ${await myContract.methods.data().call()}`);
}

//Slightly easier (web3#sendTransaction())
const init2 = async () => {
  const web3 = new Web3(infuraUrl);
  const networkId = await web3.eth.net.getId();
  const myContract = new web3.eth.Contract(
    MyContract.abi,
    MyContract.networks[networkId].address
  );
  web3.eth.accounts.wallet.add(privateKey);

  const tx = myContract.methods.setData(2);
  const gas = await tx.estimateGas({from: address});
  const gasPrice = await web3.eth.getGasPrice();
  const data = tx.encodeABI();
  const nonce = await web3.eth.getTransactionCount(address);
  const txData = {
    from: address,
    to: myContract.options.address,
    data: data,
    gas,
    gasPrice,
    nonce, 
    chain: 'rinkeby', 
    hardfork: 'istanbul'
  };

  console.log(`Old data value: ${await myContract.methods.data().call()}`);
  const receipt = await web3.eth.sendTransaction(txData);
  console.log(`Transaction hash: ${receipt.transactionHash}`);
  console.log(`New data value: ${await myContract.methods.data().call()}`);
}

//Easy way (Web3 + @truffle/hdwallet-provider)
const init3 = async () => {
  const provider = new Provider(privateKey, 'https://rinkeby.infura.io/v3/74aa9a15e2524f6980edb8a377301f3c'); 
  const web3 = new Web3(provider);
  const networkId = await web3.eth.net.getId();
  const myContract = new web3.eth.Contract(
    MyContract.abi,
    MyContract.networks[networkId].address
  );

  console.log(await myContract.methods.data().call());
  console.log(`Old data value: ${await myContract.methods.data().call()}`);
  const receipt = await myContract.methods.setData(3).send({ from: address });
  console.log(`Transaction hash: ${receipt.transactionHash}`);
  console.log(`New data value: ${await myContract.methods.data().call()}`);
}

init3();

Read more docs: https://web3js.readthedocs.io/en/v1.2.1/web3-eth.html#sendtransaction

#node #nodejs #web3 #eth #ethereum